Modern hearing aids comprise an earmold having therein the necessary electronics for amplifying and otherwise conditioning sound to compensate for a user's hearing loss. Such electronics generally include a microphone for receiving the sound and converting the sound to an electrical signal, an electronic circuit for amplifying and processing the signal produced by the microphone, a speaker (also known as a receiver) for converting the processed signals into sound energy and a battery for providing operational power to the hearing aid. The earmold can be generally made of plastic, and is specially designed and molded to fill the ear of the person who is to use the hearing aid. Generally, the earmold is made of a hard plastic so as to have a long life and so that it can be periodically cleaned. The electronics of the signal processing circuitry are typically adjusted to meet its users specific hearing requirements. These requirements are obtained by first testing the user's hearing and then providing a circuit having a frequency response characteristic that compensates for any hearing loss discovered in the test. After the desired circuit is determined from the tests, it may be finally adjusted by a hearing aid specialist to meet the final requirements of the party. All of the above features of the structure of the hearing aid, the method of making it and the method of adjusting it make the hearing aid relatively expensive.
Conventionally, hearing aids have a battery that must be replaced periodically as it is small and has only a limited lifetime of operation. Hearing aid users frequently complain about the difficulty in replacing batteries. Batteries are becoming increasingly difficult to handle as hearing aids and batteries become smaller. It is especially difficult for the majority of hearing aid wearers who are over 65 years of age and who are losing visual and motor abilities. Having a hearing aid that does not require battery replacement, or replacement at fewer time intervals, would be advantageous to these users.